High temperature ALD inlet manifold

ABSTRACT

A system and method for distributing one or more gases to an atomic layer deposition (ALD) reactor. An integrated inlet manifold block mounted over a showerhead assembly includes high temperature (up to 200° C.) rated valves mounted directly thereto, and short, easily purged reactant lines. Integral passageways and metal seals avoid o-rings and attendant dead zones along flow paths. The manifold includes an internal inert gas channel for purging reactant lines within the block inlet manifold.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/654,372, entitled HIGH TEMPERATURE ALD INLET MANIFOLD, filed on Jan.17, 2007, which claims the benefit of U.S. Provisional Application No.60/760,243, entitled HIGH TEMPERATURE ALD INLET MANIFOLD, filed on Jan.19, 2006. The subject matter of each of the aforementioned applicationsis hereby incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a manifold assembly for anatomic layer deposition (ALD) reactor.

2. Description of the Related Art

Atomic layer deposition (ALD) is a well known process in thesemiconductor industry for forming thin films of materials on substratessuch as silicon wafers. ALD is a type of vapor deposition wherein a filmis built up through deposition of multiple ultra-thin layers with thethickness of the film being determined by the number of layersdeposited. In an ALD process, gaseous molecules of one or more compounds(precursors) of the material to be deposited are supplied to thesubstrate or wafer to form a thin film of that material on the wafer. Inone pulse, typically less than 1 monolayer of a first precursor materialis adsorbed largely intact in a self-limiting process on the wafer. Theadsorbed precursor material may be decomposed or otherwise reacted in asubsequent reactant pulse or pulses to form a single molecular layer ofthe desired material. For example, the adsorbed precursor material mayreact with the reactant of a subsequent reactant pulse to form a singlemolecular layer of an element or a compound. Examples include reactantpulses that merely strip ligands from the adsorbed species, reactantsthat replace ligands with other species to form compounds, and sequenceswith three or more reactant and/or precursor pulses per cycle. Thickerfilms are produced through repeated growth cycles until the targetthickness is achieved.

In an ALD process, one or more substrates with at least one surface tobe coated are introduced into the reactor or deposition chamber. Thewafer is typically heated to a desired temperature above thecondensation temperature but below the thermal decomposition temperatureof the selected vapor phase reactants. One reactant is capable ofreacting with the adsorbed species of a prior reactant to form a desiredproduct on the substrate surface. The product can be in the form of afilm, liner, or layer.

During an ALD process, the reactant pulses, all of which are typicallyin vapor or gaseous form, are pulsed sequentially into the reactor withremoval steps between reactant pulses. For example, inert gas pulses areprovided between the pulses of reactants. The inert gas purges thechamber of one reactant pulse before the next reactant pulse to avoidgas phase mixing or CVD type reactions. A characteristic feature of ALDis that each reactant (whether a precursor contributing species to thefilm or merely a reducing agent) is delivered to the substrate until asaturated surface condition is reached. The cycles are repeated to forman atomic layer of the desired thickness. To obtain a self-limitinggrowth, sufficient amount of each precursor is provided to saturate thesubstrate. As the growth rate is self-limiting, the rate of growth isproportional to the repetition rate of the reaction sequences, ratherthan to the flux of reactant and/or temperature as in CVD.

SUMMARY OF THE INVENTION

The systems and methods of the present invention have several features,no single one of which are solely responsible for its desirableattributes. Without limiting the scope of this invention as expressed bythe claims which follow, its more prominent features will now bediscussed briefly. After considering this discussion, and particularlyafter reading the section entitled “Detailed Description of thePreferred Embodiments,” one will understand how the features describedherein provide several advantages over traditional ALD mixing methodsand systems.

One aspect is an atomic layer deposition device. The device comprises amanifold body having a first passageway and a second passageway, thefirst passageway and the second passageway having no o-rings. The devicefurther comprises a bore located within the body and in flowcommunication with the first passageway and the second passageway. Thedevice also comprises a vapor deposition chamber in flow communicationwith the bore and configured to deposit a thin film on a wafer mountedtherein.

Another aspect is a multi-piece manifold assembly for a semiconductorprocessing device. The manifold assembly comprises a body comprising afirst metallic material and having a bore and a base plate comprisingthe first metallic material and being coupled to the body. The assemblyfurther comprises a cap comprising a second metallic material and beingbonded to the base plate, the cap being configured to mount a valvethereon. The assembly also comprises an internal passage formed betweenthe bore of the body and the cap. At least a portion of the internalpassage extends through the body and the base plate without forming deadlegs at a bond interface between the body and base plate.

Another aspect is an atomic layer deposition device that comprises adispersion assembly configured to disperse gas and an inlet manifoldblock mounted over the dispersion assembly and having a bore, a firstinternal reactant line, and a second internal reactant line, the firstand second internal reactant lines being in flow communication with thebore. The assembly further comprises a first reactant valve mounted onthe inlet manifold block and configured to control a supply of a firstreactant gas to the first internal reactant line and an inert gas valvemounted on the inlet manifold block and configured to control a supplyof an inert gas to the first reactant gas valve. The assembly furthercomprises a second reactant valve coupled to the inlet manifold blockand configured to control a supply of a second reactant gas to thesecond internal reactant line and a second inert gas valve mounted onthe inlet manifold block and configured to control a supply of the inertgas to the second reactant gas valve.

Still another aspect is a method of distributing gases to an atomiclayer deposition device having a manifold and a reactor. The methodcomprises routing a first reactant gas to the manifold via a firstpassageway having no o-rings between a first reactant valve and amanifold outlet, inhibiting the reactant gas flow, and routing an inertgas to the manifold through a second passageway upstream of the firstpassageway, the second passageway having no o-rings between a firstinert gas valve and the first passageway.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will now be described with reference to the drawings ofseveral preferred embodiments, which embodiments are intended toillustrate and not to limit the invention.

FIG. 1 is a schematic view showing an atomic layer deposition (ALD)device according to an embodiment of the present invention.

FIG. 2 is a schematic drawing showing one example of an intermediatedispersion element applicable to the apparatus according to anembodiment of the present invention.

FIG. 3 is a schematic drawing showing one example of thin-film formationsteps according to an embodiment.

FIG. 4 is a cross sectional view of an ALD device showing a manifoldassembly coupled to an ALD reactor according to an embodiment.

FIG. 5 is a perspective view of the manifold assembly illustrated inFIG. 4.

FIG. 6 is a schematic view of gas flow paths through the manifoldassembly from FIG. 5 according to an embodiment and shows four inert gasvalves, each in flow communication with a separate reactant gas valve.

FIG. 7 is a top view of the manifold assembly from FIG. 5.

FIG. 8 is a cross-sectional view taken along lines 8-8 of FIG. 7.

FIG. 9 is an enlarged cross-sectional view taken along lines 9-9 of FIG.7, showing flow passageways among the reactant valves, the inert gasvalves, and the body of the manifold.

FIG. 10 is another embodiment of a manifold assembly havingsub-components of dissimilar materials, such as aluminum and stainlesssteel, bonded together.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Aspects and advantages of the present invention will now be describedwith reference to the drawings of several preferred embodiments, whichembodiments are intended to illustrate and not to limit the invention.Certain embodiments of a manifold body have one or more features. Thesefeatures include an internal inert gas channel, an integral heater, noo-rings or dead zones within the precursor path, and short reactant gaspassageways.

Despite the fact that ALD is prized for self-limiting reactions and thustheoretically perfectly conformal depositions without perfectly uniformconditions, various process parameters must be carefully controlled toensure a high quality of layers resulting from ALD. It has been foundthat if the reactant gases are not efficiently purged, it can lead toone precursor being present when the other precursor is pulsing, leadingto CVD reactions in the gas phase or on chamber/substrate surfacesinstead of surface ALD reactions. Purging of the reactant gases isfurther complicated by the use of o-rings to assemble subcomponents ofthe ALD device. These o-rings create small voids commonly referred to asdead legs near the o-ring sealing surface and the gas orifice supplyingthe precursor. Improper evacuation of these precursors due to trappedvolumes in these voids will cause particles, thus negatively impactingthe ALD process. These o-rings can also be the source of leaks, eitherthrough breach of the sealing surface itself or via permeability of theo-ring material selected for high temperature and chemistrycompatibility.

It is important to maintain thermal control of the precursor gas fromthe source (most likely a vessel carrying a solid precursor) to thewafer surface. There is usually a small window of thermal toleranceallowed (each precursor is different, but they follow the sameprincipal). That is, by controlling thermal aspects of the solid media,vapor draw (or the amount of precursor) is managed. When the temperatureis below critical set points, condensation to gas flow paths occurscausing negative process results and short maintenance intervals. Whenthe temperature is above critical set points, “decomposition” of themedia occurs and the process is in jeopardy. It is important to keep allthe zones as short as possible to maintain better thermal stability.

If the manifold assembly has no thermal integration or control, thetemperatures of the mixing gases may vary within the manifold assemblyand lead to CVD growth. While the addition of thermal integration to themanifold assembly may inhibit undesirable CVD reactions, it may have adetrimental impact on sub-components of the manifold assembly, forexample, the high speed valves. The high speed valves may not be ratedfor operation in an elevated temperature environment. Furthermore, deadzones along the flow path can cause the reactant gases to re-circulateupstream of the deposition chamber.

The times required to evacuate the precursor are of great importanceduring the ALD process. The ALD process is a “rapid fire” of precursorsand purge gases. The shorter the lines and better the conductance(pumping efficiency), the shorter the process time. This is paramount tothe ALD market.

FIG. 1 shows a cross section of one embodiment of the thin-filmformation apparatus 100 according to an embodiment of the presentinvention. The thin-film deposition apparatus 100 includes robotics (notshown) that convey a semiconductor substrate 15, which is a work pieceor object to be treated, from a vacuum transfer chamber (not shown) to areaction chamber 1 via a gate valve 6. The reaction chamber 1 comprisesan upper lid 2, a dispersion plate 3 (a.k.a. “showerhead plate”), anexhaust duct 4, a lower chamber 5, the substrate-transfer gate valve 6,an exhaust port 7, a substrate support 8, and an elevator mechanism 9for moving the substrate support 8 up and down.

The substrate 15 is loaded onto the substrate support 8 while thesupport 8 is in a lowered position 8′. The substrate support 8 is thenmoved upwards until the semiconductor substrate 15 is positioned at anappropriate distance from the dispersion plate 3. The support 8 islocated within the device and is configured to support the substrate 15or wafer during the deposition process. The support 8 may also beprovided with internal or external heaters (not shown) to heat thesubstrate 15 before and during processing. After the substrate 15 istransferred from the vacuum transfer chamber to the reaction chamber 1,the thin-film deposition apparatus performs a thin-film formationprocess in the reaction space 22 by cycling, for example, reactant gasesvia valves 31(a), 31(b), 31(c), and 31(d) and inert gases via valves30(a), 30(b), 30(c), and 30(d).

In certain embodiments, each reactant gas valve 31(a)-(d) is in flowcommunication and associated with an inert gas valve 30(a)-(d).Preferably, at least a portion of each reactant gas line is arranged inseries with the associated inert gas valve 30. In this way, the inertgas enters the flow path of the reactant gas preferably near, butupstream from, the associated reactant valve 31 to enhance purging ofthe entire reactant gas line.

For example, each reactant gas valve 31(a)-(d) may be a three portvalve. The three port valve has two input ports in flow communicationwith the reactant gas source and the inert gas valve. The output port ofthe three port valve is in flow communication with the reaction space22. The reactant gas valves 31(a)-(d) separately control flow of thereactant gases and the inert gases into the reaction space 22.

In certain embodiments, each inert gas valve 30(a)-(d) is a two portvalve. The two port valve has one input port in flow communication withan internal inert gas channel 610 (FIG. 4) and an output port in flowcommunication with one of the reactant gas valves 31(a)-(d). The twoport valve controls flow of the inert gas between the internal inert gaschannel 610 and an associated one of the reactant gas valves 31(a)-(d).In this exemplary arrangement, the reactant gas valve 31(a)-(d) islocated in series with and downstream of the associated inert gas valve30(a)-(d). For gases flowing towards the reaction space 22, a firstlocation is downstream from a second location if gas at the secondlocation flows towards the first location during substrate processing.

Each inert gas valve 30(a)-(d) controls the flow of inert gas to theassociated reactant gas valve 31(a)-(d). The reactant gas valve31(a)-(d) controls the flow of the inert gas received from theassociated inert gas valve 30(a)-(d) for purging the reactant vapor lineafter pulsing the reactant. For example, the inert gas source(s)associated with the reactant vapor sources connected to valves 31(a),31(b), 31(c), and 31(d) are connected to valves 30(a), 30(b), 30(c), and30(d), respectively. These inert gas source(s) can be pressurized ornot. These inert gas sources can be, for example, noble or nitrogen gassources. The ALD control system (not shown) includes memory andprocessing modules, and is programmed to control these valves and othervalves to selectively allow or prevent the various gases from reachingthe reaction space 22. For example, the flow from an inert gas valve 30enters the associated reactant gas line and may continue into thereaction chamber 1 and purge the chamber of the reactant gas.

In addition to the valves 30, 31 associated with the inert gases and thereactant gases, the ALD device may include a separate inert gas line 54and valve 32 connecting an inert gas source to the reaction chamber 1.Inert gas valve 32 provides additional inert gas to the ALD device andmay be operated continuously or on a periodic basis depending on thedesired substrate processing. In the illustrated embodiment, inert gasalso flows to the internal inert gas channel 610 via the inert channelsupply line 52 (FIG. 6). The inert channel supply line 52 may receiveinert gas via the inert gas valve 32 or a separate inert gas valve (notshown). The internal inert gas channel 610 is in flow communication withthe inert gas valves 30(a)-(d).

The ALD device 100 is configured to deposit a thin film on the substrate15 when the substrate 15 is inserted in the reaction chamber 1. Ingeneral, the ALD device receives a first reactant gas via one or more ofthe valves 31(a), 31(b), 31(c), 31(d). The ALD device 100 also receivesinert gas via one or more of the other valves 30(a), 30(b), 30(c),30(d). By switching the appropriate valves, the flow of the firstreactant gas is stopped and the deposition chamber and the gas lines arethen purged with the inert gas from one or more valves 30(a), 30(b),30(c), 30(d), along with the main purge flow from the inert gas line 54.After the reaction chamber 1 and gas lines are purged, the depositioncycle is continued with one or more of the other reactant gases. Thereactants from alternated pulses react with each other only on thesubstrate or wafer surface to form no more than a single monolayer ofthe desired product in each cycle and do not react or meet in the gasphase. It should be noted that in some operational modes an increaseddeposition speed above one monolayer per cycle can be achieved with somesacrifice to uniformity.

In embodiments of the ALD device 100, two or more reactant gases aresequentially flowed (separated by periods of purging) through the ALDdevice 100 in each cycle to form materials on the wafer. Excess of eachreactant gas in the reaction space is subsequently exhausted via anexhaust pipe 24 after adsorbing or reacting in the reaction space 22.The exhaust pipe 24 may be connected to a turbo molecular pump (TMP) 50to assist in the removal of the gases from the reaction chamber 1 andprovide a low pressure condition in the reaction chamber 1. Furthermore,the entire ALD device 100 can be pumped down to a low pressure byconnecting any of the couplings on the bottom of the ALD device 100 to avacuum pump (TMP 50 or dry pump (DRY).

The ALD device 100 includes a gas introduction manifold assembly 10. Themanifold assembly 10 includes a body 27 (FIG. 5), the internal inert gaschannel 610, and a central bore 28. The manifold assembly 10 furtherincludes one or more of the reactant gas valves 31(a), 31(b), 31(c),31(d), one or more of the inert gas valves 30(a), 30(b), 30(c), 30(d).The manifold assembly 10 is configured to route reactant gases enteringvia the reactant valves 31(a), 31(b), 31(c), 31(d) and inert gasesentering via inert gas valves 30(a), 30(b), 30(c), 30(d) through the ALDdevice 100 (see FIG. 3). The manifold assembly 10 is further configuredto selectively mix one or more of the inert gases entering via valves30(a)-(d) with one of reactant gases entering via valves 31(a)-(d)during a given pulse. The resulting mixture enters the reaction chamber1. After each pulse, the ALD device 100 exhausts any unreacted reactantand inert gases from the reaction chamber 1 via the exhaust pipe 24,such as through purging. The locations of the valves shown herein arefor illustrative purposes only and can be located at different locationsalong a gas line. Preferably the valves are located in close proximityto or on the manifold assembly 10 itself to reduce the length of the gasline downstream of the valve. The reactant gas valves 31(a)-31(d) may,for example, be disposed approximately 10 mm from the inlet manifoldblock, to provide a short and easily purged line. As will be describedbelow, the various valves in the exemplary embodiments described hereinare designated to flow a gas or a mixture of one or more gases into themanifold assembly 10. However, the invention is not limited to theexemplary embodiments disclosed herein.

The order that the reactant gases are cycled through the ALD device 100depends on the desired product. To minimize any interaction between oneor more reactant gases prior to each gas entering the reaction chamber1, the inert gas entering via valves 30(a)-(d) is periodically cycled orcontinuously flowed through the ALD device 100 between pulses of thereactant gases. In this way, the inert gases purge the lines and thereaction chamber 1. As will be explained below, various reactant gasesand inert gases are systematically cycled through the ALD device 100 soas to form a deposit on the wafer inserted through the gate valve 6.

As best seen in FIG. 4, the gas-introduction manifold assembly 10 ismounted over the dispersion plate 3. The manifold assembly 10 is coupledto a tubular gas-introduction member 11 that extends through the lid 2(see FIG. 1). An embodiment of the manifold assembly 10 is describedbelow in connection with FIG. 1. The member 11 connects to a downstreamend of the manifold assembly 10 and receives reactant and inert gasesfrom the manifold assembly 10. Exemplary inert gases include nitrogenand argon gas. The deposition process utilizes the inert gases to purgeand or mix with the reactant gases. A radical source 12 is shown in theillustrated embodiment connected to the manifold assembly 10 via a valve16, which may be a fully-opening valve. In certain embodiments, thevalve 16 is a dual action gate valve. Opening of the valve 16 introducesradicals from various gases into the manifold assembly 10. The member 11is in flow communication with a gas-dispersion portion 13. Gas flowingfrom the member 11 is diffused by the gas-dispersion portion 13. Theremote plasma is primarily used for chamber cleaning but may also beused for processing.

In certain embodiments, the member 11 has an intermediate dispersionmechanism 43. FIG. 2 is a schematic drawing showing one example of anintermediate dispersion element 43. The illustrated intermediatedispersion element 43 has a cylindrical shape as shown in FIG. 2 and canbe attached to the downstream end or tip of the member 11 (see FIG. 1).In certain embodiments, one or more pores or slits 44 in the walls ofthe element 43 provide diffuse flow exit paths for gas entering from themember 11. The pores 44 may be located so as to evenly discharge the gasin a radial direction away from the element 43. In addition to orinstead of pores 44, one or pores 45 may extend through the bottomsurface of the element 43 discharging gas in a vertical directiontowards the dispersion plate 3. Preferably, the one or more pores 45 donot line up with the pores in the dispersion plate 3, for betterdistribution of gases across the plate 3.

The cross-sectional profile of the gas-dispersion portion 13 illustratedin FIG. 1 has a horn shape. In order to accommodate changes in exhaustflow through the reaction chamber 1 in a short period of time, aninternal capacity of the gas-dispersion portion 13 is preferably small.In certain embodiments, the gas-dispersion portion 13 has a flattruncated cone shape with approximately an angle of 3-30 degreesrelative to the horizontal lower surface of the gas-dispersion portion13. Embodiments may include angles of 5, 10, 15, 20, 25, and valuesbetween these values, but preferably approximately 5-15 degrees, so asto more evenly distribute the dispersed gas.

In certain embodiments, a distance between the lower surface of thegas-dispersion portion 13 and the gas-dispersion plate 3 isapproximately 2-10 mm, including 3 mm, 5 mm, 7 mm, and values betweenthese values. Having the dispersion portion 13 closer to the dispersionplate 3 may more evenly distribute the gas across the plate 3. Incertain embodiments, the shape of internal walls of the gas-dispersionportion 13 may be smooth so as to promote smooth gas flow.

In certain embodiments, a heater 42 is provided in an internal wall ofthe dispersion portion 13. The heater 42 heats gas entering thedispersion portion 13. A second heater 26 may be provided in thedispersion plate 3, particularly at the peripheral edge, so as to adjustthin-film formation.

A slit exhaust port 17 is formed between a tip of the gas-dispersionportion 13 and the dispersion plate 3. The slit has an annular (e.g.circular) shape extending around the outer tip of the dispersion portion13. Various shapes for the exhaust port may be utilized but ispreferably selected so as to minimize regions where the gas flow ishydrodynamically disrupted. For example, the shape of the exhaust portcan have multiple circular-arc-shaped slits, multiple circular pores,etc. The width of the opening through the slits or pores 17 may be thesame as the distance between the lower surface of the gas-dispersionportion 13 and the gas-dispersion plate 3, or approximately between 2 mmand 5 mm.

The exhaust slit 17 is communicatively connected with an upper space 18.The upper space 18 is formed by an upper external wall of the dispersionportion 13 and the lower surface of the upper lid 2. The upper space 18is communicatively connected with a showerhead plenum 14 located betweena lower surface of the gas dispersion portion 13 and the dispersionplate 3. In certain embodiments, the distance between the upper externalwall of the dispersion portion 13 and the lower surface of the upper lid2 is approximately the same as the distance between the lower surface ofthe gas dispersion portion 13 and the dispersion plate 3.

An exhaust flange 19 connects to the upper lid 2 and receives gasexhausted from the upper space 18 and the showerhead plenum 14. Openingand closing of a showerhead exhaust valve 20 allows or prevents gas fromexhausting from the upper space 18 and the showerhead plenum 14.

As gas pressure drops when the gas passes through the upper space 18 viathe slit 17, it may be make it more difficult to exhaust the gas over ashort period of time between reactant pulses. Consequently, in certainembodiments, it may be advantageous to have a duct extending through theslit 17 and connecting to the exhaust flange 19. It has been found thatan annular duct increases gas flow to the exhaust flange 19 as comparedto embodiments with the upper space 18. This is because the internalsurface area of the duct which contacts the gas is less than the surfacearea contacted by the gas when it flows from the upper space 18.However, because the exhaust flange 19 is located offset relative to theannular duct, the annular duct does not uniformly exhaust gas ascompared to embodiments using the upper space 18. For example, inembodiments using the upper space 18, the exhaust flange 19 can belocated near the center of the upper space 18 and receive exhausted gasuniformly.

The gas passes through the gas-dispersion portion 13 and reaches theshowerhead plenum 14. The gas further travels through gas-dischargeports 21 in the dispersion plate 3. The gas that passes through thegas-discharge ports 21 reaches the reaction space 22 between thesubstrate support 8 and the dispersion or showerhead plate 3. The gasmay then continue and reach a surface of the substrate 15. The gas thenmay continue through a ring-shaped slit 23 formed in the exhaust duct 4and be exhausted from an exhaust pipe 24 communicatively connected withthe slit 23. In certain embodiments, the gas flow rate from thedispersion plate 3 and to the reaction space 22 is approximately 2-3liters/sec.

By feeding radio-frequency power to the dispersion plate 3 from anelectrode 25, plasma can be generated between the dispersion plate 3 andthe substrate support 8. For example, in situ plasma is created betweenthe dispersion plate 3 and the substrate support 8 for plasma enhancedatomic layer deposition (PEALD) processing. Remote plasma creation isused for performing certain processes of PEALD and for periodic reactionchamber 1 cleaning between substrate 15 processing, for example betweenevery lot of wafers. The remote plasma is generated using an ex-situplasma generator illustrated as the remote radical or excited speciessource 12. The generator may operate at, for example, a frequency of 400kHz and be obtained from MKS Instruments located in Wilmington, Mass.The generator may be mounted on top of the manifold assembly 10 orfurther upstream. The valve 16 separates the remote plasma generatorfrom the manifold assembly 10. Radicals are generated in the remoteplasma generator either for chamber cleaning or deposition. The radicalsare allowed to flow/drift/diffuse throughout the dispersion portion 13and to the surface of the substrate 15. Preferably the radical source 12is mounted close to the chamber 1 and the valve 16 opens wide tomaximize excited species survival and thus cleaning efficiency.

An RF generator for the in-situ direct plasma generation may operate at,for example, 13.56 MHz. Such an RF generator and a matching network maybe obtained from ADTEC Technology Inc. located in Fremont, Calif. Thematching network may be mounted on top of the reaction chamber 1. Atransmission line is connected between the output of the matchingnetwork and the dispersion plate 3. The dispersion plate 3 (FIG. 1),dispersion portion 13 (FIG. 1) and upper lid ring 113 (FIG. 4) are RFhot. The remainder of the conductive elements defining the reactionspace 22, particularly the substrate support 8, is at ground. The directplasma is generated only between the dispersion plate 3 and thesubstrate support 8.

Once processing is complete, the substrate support 8 is lowered and thesubstrate 15 can be removed from the deposition chamber via the samegate valve 6.

A control system (not shown) is configured to control the apparatusduring processing of the substrate 15. For example, the control systemcan include a computer control system and electrically controlled valvesto control the flow of reactant and inert gases into and out of thedevice and the application of RF power. The control system can includemodules such as a software or hardware component, such as a FPGA orASIC, which performs certain tasks. A module may advantageously beconfigured to reside on the addressable storage medium of the computercontrol system and be configured to execute on one or more processors.

FIG. 3 shows a representative sequence for introducing gases to thereaction chamber 1. In Step 1 shown in FIG. 3, the showerhead exhaustvalve 20 is closed. Reactant gas valve 31(a) is opened to allow Gas A toenter a central bore 28 of the manifold assembly 10. In this example,Gas A continues into the gas-dispersion portion 13, passes through thedispersion plate 3, and is supplied into the reaction space 22. Gas A isexhausted from the reaction space 22 through the exhaust slit 23 and tothe exhaust pipe 24.

After Gas A is supplied for a given period of time, in Step 2, thereactant gas valve 31(a) for Gas A is configured to prevent gas A fromentering the central bore 28 of the manifold assembly 10 and allow aninert gas flowing from the inert gas valve 30(a) to enter the centralbore 28 of the manifold assembly 10. At this time, depending on theparticular process or chemistry involved, the showerhead exhaust valve20 may be fully opened. The remaining Gas A is purged by the inert gas.The inert gas is introduced from the inert gas valve 30(a) into thereactant gas line used for Gas A at a point upstream of reactant gasvalve 31(a). In this way, the inert gas flows through the reactant gasvalve 31(a) and flushes or purges the reactant gas lines to preventreactant diffusion during subsequent steps. Internal inert gas channel610 (see FIG. 4) supplies the inert gas entering the inert gas valve30(a). In certain embodiments, the internal inert gas channel 610 islocated within the manifold assembly 10.

In Step 3, the reactant gas valve 31(a) is configured to prevent bothreactant Gas A and the inert gas from entering the central bore 28 ofthe manifold assembly 10. The inert gas valve 30(a) in FIG. 3 is closedin step 3, but this does not have to be the case. In the illustratedembodiment, where it is desirable to halt inert gas through thischannel, the three-way reactant gas valve 31(a) prevents inert gas fromentering the central bore 28 of the manifold assembly 10 regardless ofthe configuration of the inert gas valve 30(a).

Gas B is introduced in the central bore 28 of the manifold assembly 10by opening the reactant gas valve 31(b). In this case, Gas B isintroduced from the gas-introduction portion 11 (FIG. 1) and into thegas-dispersion portion 13. Gas B then continues through the dispersionplate 3 and is supplied onto the substrate surface 15. While traversingthe substrate surface 15, Gas B pulse saturates the surface of thesubstrate. Adsorption or reaction occurs between Gas B and the surfaceof the substrate as left by the previous pulse.

After passing across the reaction space 22 and in a radial direction,the Gas B flows towards the exhaust pipe 24 and through the exhaust slit23. The exhaust pipe 24 is configured to collect excess gas and anybyproduct after the gas has saturated the wafer. In an embodiment, aregion within the exhaust pipe 24 is at a lower pressure than thepressure in the reaction chamber 1. A negative pressure source or vacuumcan be in flow communication with the exhaust pipe 24 and/or exhaustslit 23 to draw the gas from the reaction chamber 1. Gas B is exhaustedfrom the exhaust slit 23 to the exhaust pipe 24.

After a given period of time, the reactant gas valve 31(b) is closed andthe supply of Gas B is shut off. In the state similar to that shown inStep 2, except with inert gas flowing through the Gas B channel insteadof the Gas A channel, the remaining Gas B is exhausted from the valve20. By repeating the supply of reaction Gas A and the supply of reactionGas B as part of these four steps, each cycle deposits less than amolecular monolayer. The skilled artisan will appreciate that sterichindrance from the bulky precursors tends to block reactive sites andreduce growth rates to less than a monolayer per cycle.

Even if three kinds or more of reaction gases are used, film formationcan be easily achieved by repeating steps of supplying three kinds ormore of reaction gases and steps of purging respective gases.

In certain embodiments, it is possible to easily purge an inner area ofthe dispersion plate 3 by opening or closing the showerhead exhaustvalve 20. Additionally, because the degree which the valve 20 is openedor closed may be varied, complete shut-off is not required.

Also, in certain embodiments, depending on chemistry, one or more of thereactant lines (A, B, C, D) can be open at all times during the process.This may occur, for example, when the reactant gas sources act asreducing agents for the precursors delivered in pulse steps, which onlyreact when RF power is applied.

When applying radio-frequency power to the gas-dispersion plate 3, thereaction gas can also be supplied as a direct plasma gas. By providingthe heater 42 (FIG. 1) in the gas-dispersion portion 13, it is possibleto raise temperatures of the inside of the dispersion portion 13.Consequently, when using organic metal materials which have low vaporpressure and easily cohere, it becomes possible to exhaust them withoutcohesion.

FIG. 4 is a cross sectional view showing in detail an embodiment of theALD device 100. This figure does not show a substrate support orsusceptor and all gas valves. Gas A reactant gas is introduced to themanifold assembly 10 through valve 31(a). Gas A is then introduced intoa first compartment 82 of the dispersion portion 13 through the slits 44in the intermediate dispersion element 43. The first compartment 82 isdefined in part by a bottom plate having slits. Gas A reactant gaspasses through the slits and flows into a second compartment 81 which isabove an upper surface of the dispersion plate 3 having a plurality ofbores (not shown). The first compartment 82 and the second compartment81 constitute a showerhead plenum.

In certain embodiments, the first compartment 82 does not have a bottomplate and there is no clear boundary between the first compartment 82and the second compartment 81. Gas A is discharged to the reaction space22 of the reaction chamber 1 through the bores formed in the dispersionplate 3. The reaction space 22 is located above the substrate support 8(FIG. 1). During the above process, the reaction space 22 is constantlyexhausted using an exhaust duct 4 through an annular slit 23, whereinthe gas is drawn radially toward the outer periphery of the reactionspace 22. The annular slit 23 is located around the outer periphery ofthe substrate support 8. The gas dispersion portion 13 is fixed to thedispersion plate 3 via an upper lid ring 113 above which an insulationplate 150 is placed.

The gas dispersion portion 13 and the dispersion plate 3 do not directlycontact each other, and an annular gap 83 is formed along the outerperiphery of the gas dispersion portion 13. This annular gap 83communicates with the exhaust flange 19 (see FIG. 1) through the upperlid plate 113.

When purging the first and second compartments 82, 81, a purge gas isintroduced thereto through one of the valves 30(a)-(d), an associatedone of the reactant gas valves 31(a)-(d), the manifold assembly 10, andthe intermediate dispersion element 13. The main purge flows from theinert gas line 54 and through the manifold assembly 10. Inert gas fromthe reactant gas valves 31(a)-(d) and the inert gas valves 30(a)-(d)flush or purge the lines between the reactant valves and the centralbore 28. Simultaneously, the first and second compartments 82, 81, areevacuated using the exhaust flange 19 through the annular gap 83. Thereaction space 22 is constantly evacuated through the slit 23 and theexhaust duct 4.

As best seen in FIG. 5, in this example, the manifold assembly 10includes four reactant gas valves 31(a)-(d), an inert channel supplyline 52, and an inert mixer supply line 54. Each reactant valve31(a)-(d) is paired with an inert gas valve 30(a)-(d). Reactant valve31(a) is coupled to inert valve 30(a). Reactant valve 31(b) is pairedwith inert valve 30(b). Reactant valve 31(c) is paired with inert valve30(c). Reactant valve 31(d) is paired with inert valve 30(d). The ALDdevice 100 can include greater or fewer reactant valves and inert valvesdepending on the configuration of the ALD device 100. Moreover, eachreactant line may or may not be paired to one inert gas valve. Forexample, one or more of the reactant lines may be paired to the inertgas valves while another reactant line is not. The reactant line that isnot paired to the valves could be purged by other means.

Coupling 190(a) couples the reactant gas valve 31(a) to a reactantsource A 620 (FIG. 6). Coupling 190(b) couples the reactant gas valve31(b) to a reactant source B 626 (FIG. 6). Coupling 190(c) couples thereactant gas valve 31(c) to a reactant source C 632 (FIG. 6). Coupling190(d) couples the reactant gas valve 31(d) to a reactant source D 638(FIG. 6).

Coupling 190(f) couples the internal inert gas channel 610 (see FIG. 6)to an inert or purge gas source 644 (FIG. 6). Coupling 190(e) couplesthe central bore 28 or inside of the manifold assembly 10 with the inertgas source 644 separately from the internal inert gas channel 610.

In the embodiment illustrated in FIG. 5, inert channel supply line 52and couplings 190(a)-(d) provide a flow path to a valve and toward theinside of the manifold assembly 10. Inert channel supply line 52connects to the internal inert gas channel 610. In the illustratedembodiment, each of the inert gas valves 30(a)-(d) are locateddownstream of the internal inert gas channel 610. Line 54 provides apath to the inside of the manifold assembly 10 without passing through avalve.

In the embodiment shown in FIG. 5, the couplings 190(a)-(d) flowreactant gases into the manifold assembly 10. The inert gas line 54provides a passageway to flow inert gas directly to the central bore 28.The resulting mixture (one reactant at a time with an inert gas) flowsdownward toward the reaction chamber 1. An insulator plate 56 liesadjacent to an insulation plate 150 (FIG. 4) when assembled on the ALDdevice 100.

The manifold assembly 10 includes one or more heater cartridges 180configured to control wall temperature. The reactant gas passing throughthe manifold assembly 10 is heated by the manifold and heater cartridges180. Controlling the temperature of the reactant gases as they passthrough the manifold assembly 10 reduces the likelihood thatcondensation or thermal decomposition of the gas will occur. In certainembodiments, each reactant gas valve 31(a)-(d) is separately heated byone or more heater cartridges 180.

In the illustrated embodiment, two of the reactant valves have heatersto facilitate use of precursors with low vapor pressure (e.g., liquid orsolid at standard conditions, such as ZrCl₂, HfCl₂, TMA and othermetalorganics), while two do not. For example, a first set of one ormore heater cartridges 180 may be located within the manifold assembly10 and near to the lines carrying reactant gas A. A second set of one ormore heater cartridges 180 may be located within the manifold assembly10 and near to the lines carrying reactant gas B. The first and secondsets of heater cartridges 180 may be separately controlled so as to heatgas A to a different temperature than gas B. In certain embodiments, theheater cartridges 180 maintain a wall temperature up to 200° C. withinthe manifold assembly 10. One or more thermal switches may be employedto monitor the temperature of the manifold assembly 10. It will beunderstood that the system includes other temperature sensor and controlmechanisms to maintain various components of the system at desiredtemperatures.

Further, the system may maintain a different temperature for a firstpair of valves 30, 31 and a second temperature for a second set ofvalves 30, 31 depending on the desired processing. While the illustratedembodiment contemplates heater cartridges driven by temperaturesensor(s) defining a single zone for temperature control of themonolithic ALD inlet manifold, the illustrated embodiment can also beadapted for separated zone control for each precursor within the ALDmanifold. For example, in the illustrated case of 4 precursors withseparate manifold paths, five zones can be provided for separate thermalcontrol of the flow path for each precursor: the center hub and each ofthe four precursor lines (including valves) are treated as separatezones. To facilitate thermal separation of zones, the hub could bemanufactured with a thermal air break limiting the mechanical andthermal connection between, for example, the body 27 and a base plate606 (see FIG. 10) to small spot protrusions around the precursor gasinlet apertures. Additional heaters and thermocouples to monitor thermalcontrol would be employed. Advantageously, temperatures of the flowpaths upstream of the mixing point (e.g., the central bore) can beseparately tuned for each reactant to minimize coating of the lines,whether by condensation, reaction or adsorption, and thus minimizeclogging and/or downstream contamination.

FIG. 6 is a schematic view of gas flow paths through the manifoldassembly 10 illustrated in FIG. 5 and shows four inert gas valves31(a)-(d), each in flow communication with separate reactant gas valves30(a)-(d). The manifold assembly 10 includes an internal inert gaschannel 610 in flow communication with the four inert gas valves30(a)-(d). FIG. 6 further illustrates the source for each reactant andinert gas. The reactant sources may represent gas containers, bubblersor other vaporizers, depending on whether reactants are solid, liquid,or gas under standard conditions. Additional valves (not shown)associated with the reactant and inert gas sources may be locatedoutside of the manifold assembly 10.

Gas A flows from its source 620 and through line 622 before reachingreactant valve 31(a). Reactant gas valve 31(a) may be configured toallow or prevent flow of gas A through line 624 and into the centralbore 28 of the manifold assembly 10 depending on the desired processingstep. Gas B flows from its source 626 and through line 628 beforereaching reactant valve 31(b). Reactant gas valve 31(b) may beconfigured to allow or prevent flow of gas B through line 630 and intothe central bore 28 of the manifold assembly 10 depending on the desiredprocessing step.

Gas C flows from its source 632 and through line 634 before reachingreactant valve 31(c). Reactant gas valve 31(c) may be configured toallow or prevent flow of gas C through line 636 and into the centralbore 28 of the manifold assembly 10 depending on the desired processingstep. Gas D flows from its source 638 and through line 640 beforereaching reactant valve 31(d). Reactant gas valve 31(d) may beconfigured to allow or prevent flow of gas D through line 642 and intothe central bore 28 of the manifold assembly 10 depending on the desiredprocessing step. The illustrated four reactant valve embodiment isexemplary and more or less reactant valves could be used.

The inert gas flows from source 644 (which may include multiple gascontainers) and through the inert channel supply line 52 before reachingthe internal inert gas channel 610. The internal inert gas channel 610is preferably located within the manifold assembly 10. By including theinert gas channel 610 within the manifold assembly 10, maintenanceproficiency is enhanced. Advantageously, the manifold assembly 10 may betested on a bench prior to re-assembly onto the reactor. With the inertgas channel 610 included in the manifold assembly 10, thermal control ofthe inert gas is more uniform with the precursor gas since the inert gasand the precursor gas are fed through the same thermal mass or manifoldassembly 10.

When the inert gas channel is located outside the manifold and insidethe reactor top, additional o-rings are required in the chamber. Theseadditional o-rings can affect vacuum integrity of the reactor. Cleaningmay also be more complicated since the entire reactor is disassembled toaccess an inert gas channel that is located within the reactor.

The internal inert gas channel 610 is further in flow communication withone or more of the inert gas valves 30(a)-(d). In the exemplaryembodiment illustrated in FIG. 6, the internal inert gas channel 610 isin flow communication with four inert gas valves 30(a)-(d).

The inert gas flows from the internal inert gas channel 610 and throughline 646 before reaching inert gas valve 30(a). In certain embodiments,the inert gas valve 30(a) is a two port valve. The two port valvecontrols flow of the inert gas between the internal inert gas channel610 and the reactant gas valve 31(a). The two port valve has one inputport in flow communication with the internal inert gas channel 610 andan output port in flow communication with reactant gas valve 31(a) vialine 648. In this way, the inert gas valve 30(a) may be configured toallow or prevent flow of inert gas between line 646 and line 648.

Reactant gas valve 31(a) is in flow communication with line 648. Inaddition to allowing or preventing reactant gas A from reaching thecentral bore 28 of the manifold assembly 10 from line 622 as describedabove, the reactant gas valve 31(a) is further configured to allow orprevent flow of inert gas through line 624 and into the central bore 28of the manifold assembly 10. Thus, the reactant gas valve 31(a) may beconfigured to separately allow or prevent the inert gas and the reactantgas A from entering line 624.

In a preferred embodiment, reactant gas valve 31(a) is a three portvalve. A first port of reactant gas valve 31(a) is in flow communicationwith line 622 and receives reactant gas A. A second port of reactant gasvalve 31(a) is in flow communication with line 648 and receives an inertgas. A third or exit port for reactant gas valve 31(a) is in flowcommunication with the central bore 28 of the manifold assembly 10 vialine 624.

The inert gas flows from the internal inert gas channel 610 and throughline 650 before reaching inert gas valve 30(b). In certain embodiments,the inert gas valve 30(b) is a two port valve. The two port valvecontrols flow of the inert gas between the internal inert gas channel610 and the reactant gas valve 31(b). The two port valve has one inputport in flow communication with the internal inert gas channel 610 andan output port in flow communication with reactant gas valve 31(b) vialine 652. In this way, the inert gas valve 30(b) may be configured toallow or prevent flow of inert gas between line 650 and line 652.

Reactant gas valve 31(b) is in flow communication with line 652. Inaddition to allowing or preventing reactant gas B from reaching thecentral bore 28 of the manifold assembly 10 from line 628 as describedabove, the reactant gas valve 31(b) is further configured to allow orprevent flow of inert gas through line 630 and into the central bore 28of the manifold assembly 10. Thus, the reactant gas valve 31(b) may beconfigured to separately allow or prevent the inert gas and the reactantgas B from entering line 630.

In a preferred embodiment, reactant gas valve 31(b) is a three portvalve. A first port of reactant gas valve 31(b) is in flow communicationwith line 628 and receives reactant gas B. A second port of reactant gasvalve 31(b) is in flow communication with line 652 and receives an inertgas. A third or exit port for reactant gas valve 31(b) is in flowcommunication with the central bore 28 of the manifold assembly 10 vialine 630.

The inert gas flows from the internal inert gas channel 610 and throughline 654 before reaching inert gas valve 30(c). In certain embodiments,the inert gas valve 30(c) is a two port valve. The two port valvecontrols flow of the inert gas between the internal inert gas channel610 and the reactant gas valve 31(c). The two port valve has one inputport in flow communication with the internal inert gas channel 610 andan output port in flow communication with reactant gas valve 31(c) vialine 656. In this way, the inert gas valve 30(c) may be configured toallow or prevent flow of inert gas between line 654 and line 656.

Reactant gas valve 31(c) is in flow communication with line 656. Inaddition to allowing or preventing reactant gas C from reaching thecentral bore 28 of the manifold assembly 10 from line 634 as describedabove, the reactant gas valve 31(c) is further configured to allow orprevent flow of inert gas through line 636 and into the central bore 28of the manifold assembly 10. Thus, the reactant gas valve 31(c) may beconfigured to separately allow or prevent the inert gas and the reactantgas C from entering line 636.

In a preferred embodiment, reactant gas valve 31(c) is a three portvalve. A first port of reactant gas valve 31(c) is in flow communicationwith line 634 and receives reactant gas C. A second port of reactant gasvalve 31(c) is in flow communication with line 656 and receives an inertgas. A third or exit port for reactant gas valve 31(c) is in flowcommunication with the central bore 28 of the manifold assembly 10 vialine 636.

The inert gas flows from the internal inert gas channel 610 and throughline 658 before reaching inert gas valve 30(d). In certain embodiments,the inert gas valve 30(d) is a two port valve. The two port valvecontrols flow of the inert gas between the internal inert gas channel610 and the reactant gas valve 31(d). The two port valve has one inputport in flow communication with the internal inert gas channel 610 andan output port in flow communication with reactant gas valve 31(d) vialine 660. In this way, the inert gas valve 30(d) may be configured toallow or prevent flow of inert gas between line 658 and line 660.

Reactant gas valve 31(d) is in flow communication with line 660. Inaddition to allowing or preventing reactant gas D from reaching thecentral bore 28 of the manifold assembly 10 from line 640 as describedabove, the reactant gas valve 31(d) is further configured to allow orprevent flow of inert gas through line 642 and into the central bore 28of the manifold assembly 10. Thus, the reactant gas valve 31(d) may beconfigured to separately allow or prevent the inert gas and the reactantgas D from entering line 642.

In a preferred embodiment, reactant gas valve 31(d) is a three portvalve. A first port of reactant gas valve 31(d) is in flow communicationwith line 640 and receives reactant gas D. A second port of reactant gasvalve 31(d) is in flow communication with line 660 and receives an inertgas. A third or exit port for reactant gas valve 31(d) is in flowcommunication with the central bore 28 of the manifold assembly 10 vialine 642.

The terms “prevent” and “allow” are relative terms and are not limitedto the sealing off of gas flow or to permitting full flow. For example,reactant gas valve 31(a) is configured to allow reactant gas flow whenreactant gas flowing through the valve is increased. Similarly, reactantgas valve 31(a) is configured to prevent reactant gas flow when reactantgas flowing through the valve is decreased. Further, the lengths of thelines illustrated in FIG. 6 are for ease of identification and mayshorter or longer depending on the desired configuration. In certainembodiments, it may be preferred to shorten one or more lines to reducethe amount of non-reacted reactants to be purged from the manifoldassembly 10. In fact, the “lines” of FIG. 6 within the manifold assembly10 are all machined channels within the central block and/or appendedplates, such that the distances between the valves and the reactionchamber are minimal, reducing purge times, as will be appreciated fromFIGS. 4-5 and 7-10.

An inert mixer supply line 54 couples the central bore 28 or inside ofthe manifold assembly 10 with the inert gas source 644 separately fromthe internal inert gas channel 610. Line 54 provides a path to thecentral bore 28 without passing through a valve. In certain embodiments,a valve 662 controls flow of the inert gas entering the manifoldassembly 10 from line 54.

FIG. 7 is a top view of the manifold apparatus 10 from FIG. 5illustrating reactant gas valves 31(a)-(d) and inert gas valves30(a)-(d) coupled to the central body 27 of the manifold assembly 10.The manifold assembly 10 is configured to route reactant gases enteringvia couplings 190(a)-(d) and inert gas entering via coupling 190(e) tothe central bore 28 of the manifold assembly 10. The coupling 190(a) isin flow communication with reactant gas valve 31(a) via line 622. Thecoupling 190(b) is in flow communication with reactant gas valve 31(b)via line 628. The coupling 190(c) is in flow communication with reactantgas valve 31(c) via line 634. The coupling 190(d) is in flowcommunication with reactant gas valve 31(d) via line 640. The coupling190(e) is in flow communication with the central bore 28 of the manifoldassembly 10 via line 54.

The manifold assembly 10 may route a single gas or multiple gases at thesame time to the central bore 28 of the manifold assembly 10 during agiven pulse. Preferably, in ALD mode, one reactant gas is mixed withinert gas in the bore 28. The resulting mixture enters the depositionchamber 1 (FIG. 1). After each pulse, the ALD exhausts any unreactedreactant and inert gases from the deposition chamber via the exhaustpipe 24 and from the showerhead assembly via the showerhead exhaustvalve 20 (FIG. 1), such as through purging.

Inert gas may continually flow to the central bore 28 of the manifoldassembly 10 via line 54 during processing, intermittingly, or onlyduring purge operations. As discussed above, inert gas may also flow tothe internal inert gas channel 610 via the inert channel supply line 52(FIG. 6) within the manifold assembly 10. The internal inert gas channel610 is in flow communication with the inert gas valves 30(a)-(d).

The inert gas valves 30(a)-(d) attach directly to the body 27 of themanifold assembly 10. As seen in FIGS. 8 and 9, each reactant gas valve31(a)-(d) may be mounted on the body 27 using a spacer block 700(a)-(d)which attaches to the body 27. The spacer blocks 700(a)-(d) are providedwith openings and screw holes which mate with the reactant gas valves31(a)-(d). The spacer blocks 700(a)-(d) ease manufacturing of themanifold assembly 10. Spacer block 700(a) is associated with reactantgas valve 31(a) and provides flow paths between the body 27 of themanifold assembly 10 and the reactant gas valve 31(a). Spacer block700(b) is associated with reactant gas valve 31(b) and provides flowpaths between the body 27 of the manifold assembly 10 and the reactantgas valve 31(b). Spacer block 700(c) is associated with reactant gasvalve 31(c) and provides flow paths between the body 27 of the manifoldassembly 10 and the reactant gas valve 31(c). Spacer block 700(d) isassociated with reactant gas valve 31(d) and provides flow paths betweenthe body 27 of the manifold assembly 10 and the reactant gas valve31(d).

FIG. 8 is a cross-sectional view taken along lines 8-8 of FIG. 7, whileFIG. 9 is a cross-sectional view taken along lines 9-9 of FIG. 7. Eachspacer block 700(a)-(d) provides a portion of the gas routing paths toand from the associated reactant gas valve 31(a)-(d). The gas routingpaths illustrated in FIGS. 8 and 9 correspond to lines described withreference to FIG. 6. An entire line described in FIG. 6 may represent anentire passageway in a single component of the manifold assembly 10 orportions of passageways in multiple components of the manifold assembly10. For example, line 652 illustrated in FIGS. 6 and 8 corresponds to atleast portions of passageways in both the body 27 of the manifoldassembly 10 and in the spacer block 700(b). Line 660 illustrated inFIGS. 6 and 8 corresponds to at least portions of passageways in thebody 27 of the manifold assembly 10 and in the spacer block 700(d).

The body 27 in the illustrated embodiment has a tubular shape with acentral bore 28. The body 27 includes an entrance 612 and an exit 614.The central bore 28 can have a lower portion having a cylindrical shapeand an upper portion having a conical shape. The cross-sectional area inthe region of the entrance 612 is preferably greater than thecross-sectional area of the exit 614. In some embodiments, thecross-sectional flow area of the central bore 28 gradually decreases asthe mixture migrates towards the exit 614 and forms a tapered or“funnel” passage.

In certain embodiments, at least a portion of the inner surface of thebody 27 has a conical shape which reduces the open cross-section areathrough the body 27 as the mixture flows towards the exit 614. The body27 further includes attachment holes on the downstream or bottom surfacefor attaching the manifold assembly 10 to the showerhead plate of thereaction chamber 1.

In the illustrated embodiment, each spacer block 700(a)-(d) has threedistinct passageways connected to the two input ports and the singleoutput port of the associated reactant gas valve 31(a)-(d). For example,a first passageway or line 652 in both the spacer block 700(b) and thebody 27 of the manifold assembly 10 connects the output port of theinert gas valve 30(b) to one of the two input ports for the reactant gasvalve 31(b). The second passageway or line 628 connects coupling 190(b)to the other input port for the reactant valve 31(b). The thirdpassageway or line 630 connects the output port of the reactant gasvalve 31(b) with the central bore 28 of the manifold assembly 10. Withrespect to reactant gas valve 31(d), a first passageway or line 660 inboth the spacer block 700(d) and the body 27 of the manifold assembly 10connects the output port of the inert gas valve 30(d) to one of the twoinput ports for the reactant gas valve 31(d). The second passageway orline 640 connects coupling 190(d) to the other input port for thereactant valve 31(d). The third passageway or line 642 connects theoutput port of the reactant gas valve 31(d) with the central bore 28 ofthe manifold assembly 10. The inert gas valves 30(a)-(d) are partiallyobstructed from view by the reactant gas valves 31(a)-(d) in FIG. 7.

FIG. 9 is an enlarged cross-sectional view taken along lines 9-9 of FIG.7, showing reactant valves 31(a), 31(c) and inert gas valves 30(a),30(c) connected to the body 27 of the manifold assembly 10. Referring toFIGS. 7 and 9, spacer block 700(a) is associated with reactant gas valve31(a) and provides flow paths between the body 27 of the manifoldassembly 10 and the reactant gas valve 31(a). Spacer block 700(c) isassociated with reactant gas valve 31(c) and provides flow paths betweenthe body of the manifold assembly 10 and the reactant gas valve 31(c). Afirst passageway or line 648 in both the spacer block 700(a) and thebody 27 of the manifold assembly 10 connects the output port of theinert gas valve 30(a) to one of the two input ports for the reactant gasvalve 31(a). The second passageway or line 622 connects coupling 190(a)to the other input port for the reactant valve 31(a). The thirdpassageway or line 624 connects the output port of the reactant gasvalve 31(a) with the central bore 28 of the manifold assembly 10. Withrespect to reactant gas valve 31(c), a first passageway or line 656 inboth the spacer block 700(c) and the body 27 of the manifold assembly 10connects the output port of the inert gas valve 30(c) to one of the twoinput ports for the reactant gas valve 31(c). The second passageway orline 634 connects coupling 190(c) to the other input port for thereactant valve 31(c). The third passageway or line 636 connects theoutput port of the reactant gas valve 31(c) with the central bore 28 ofthe manifold assembly 10.

Passageway or line 654 connects the input port of the inert gas valve30(c) with the internal inert gas channel 610. Passageway or line 646connects the input port of the inert gas valve 30(a) with the internalinert gas channel 610.

Referring to FIGS. 8 and 9, reactant gas enters the central bore 28 ofthe manifold assembly 10 via lines 624, 630, 636, 642 preferably offcenter from a centerline 702 so as to swirl the gas within the centralbore 28 to enhance mixing. Swirling gas may promote mixing of thereactant gas with an inert gas and/or another reactant gas depending onthe desired product. The gas mixture circles around inside the tubularbody as the mixture migrates towards the deposition chamber 1.

In certain embodiments, one or more of the body 27, spacer 700(a)-(d),and valve 30(a)-(d), 31(a)-(d) components are stainless steel or othermetallic material. With stainless steel, the manifold assembly 10 neednot include o-rings, resulting in no dead zones. Advantageously, thelines or passageways are integrally formed within a chemically resistantmetal block or body 27. In certain embodiments, the inert and reactantvalves 30, 31 are stainless steel and commercially available fromSwagelok Co. of Salon, Ohio. In a preferred embodiment, the Swagelok twoport inert gas valves 30(a)-(d) are identified as part number6LVV-MSM-ALD3T-W2-P-CS and the three port reactant gas valves 31(a)-(d)are identified as part number 6LVV-MSM-ALD3T-W3-P-CS. Each of the metalvalves 30, 31 may be sealed against the metal and preferably stainlesssteel spacer 700 and body 27 of the manifolds with metal seals. Incertain other embodiments, one or more components of the manifoldassembly 10 are made from a ceramic material.

FIG. 9 further illustrates various metal seals located between surfacesof mating components. Of course, more or less metal seals could be useddepending on, for example, the materials, tolerances, operatingpressures, and gases associated with the mating components. Further, incertain embodiments, one or more components may be combined into asingle component and therefore render any seals between the combinedcomponents unnecessary. For example, the spacer block 700(a)-(d) andassociated reactant gas valve 31(a)-(d) could be combined into a singlecomponent and obviate the need for seals between the combinedcomponents. Further, the spacer block 700(a)-(d) associated with areactant gas valve may extend beyond the side of the reactant gas valveso as to form a spacer for the adjacent inert gas valve (see FIG. 10).Alternatively, the reactant gas valve and the inert gas valve associatedwith the reactant gas valve may have separate spacers. Conventionalseals 900 made from polymeric materials, such as for o-rings, are alsoemployed to seal the manifold assembly 10 against the showerheadassembly.

FIG. 10 schematically illustrates another embodiment of a manifoldassembly 10 wherein the spacer blocks comprise sub-components ofdissimilar materials, such as aluminum and stainless steel, bondedbetween the reactant gas valve 31(a) and its associated inert gas valve30(a) and the body 27 of the manifold assembly 10. For this embodiment,reactant gas valve 31(a) and inert gas valve 30(a) are illustrated whilereactant gas valves 31(b)-(d) and inert gas valves 30(b)-(d) are not.However, the following description applies equally to the other threepairs of reactant gas valves and associated inert gas valves 30(b),31(b); 30(c), 31(c); 30(d), 31(d).

In this preferred embodiment, the valves 31(a), 30(a) are made of astainless steel, for example 316 SS. Stainless steel advantageouslyincreases the durability of the valves over lesser strength metals. Thebody 27 of the manifold assembly 10 is made from an aluminum or similarmaterial and provides high thermal conductivity. Advantageously,aluminum is a relative light metal and provides enhanced thermaldistribution in comparison to stainless steel. Alternatively, the body27 may be made from 316 stainless steel. Of course other materials maybe used for the body 27.

As illustrated in FIG. 6, many internal passageways within the manifoldassembly 10 are shared between components. An interface betweenconnecting passageways in different parts conventionally employsrecesses in the mating surfaces to accommodate an o-ring or othersealing device 900 (FIG. 9). The recesses and associated seals increasethe likelihood of forming a dead zone at the interface. It isadvantageous to have fewer recessed or embedded seals, o-rings, and anyresulting dead zones along the flow paths between the central bore 28 ofthe manifold assembly 10 and the reactant and inert gas valves. Suchdead zones would provide gaps or voids which inhibit complete purge ofthe flow paths. An incompletely purged first reactant gas mayundesirably react with a second reactant gas at the site of the void orat a location along the flow path to which the first reactant candiffuse.

It has been found that by reducing the number of intermediary interfaceslocated between the body 27 and the valves 30, 31, the number of sealsis reduced along with the susceptibility for forming dead zones. Whereinterfaces must occur, advanced fabrication techniques may be utilizedto minimize the formation of dead zones at the interfaces. Thesefabrication techniques include electron beam welding, employing metalseal technology, explosion bonding, and the like. One or more of thesetechniques may be used to manufacture the manifold assembly 10.

In this preferred embodiment, one or more members are sandwiched betweenthe body 27 and the valves 31(a), 30(a). In the illustrated embodiment,an aluminum base plate 606 and a stainless steel cap 608 connect thebody 27 to the valves 30(a), 31(a). The base plate 606 and cap 608further connect to each other. Preferably, the base plate 606 and cap608 are connected together before being connected to the body 27. Incertain embodiments, the base plate 606 and the cap 608 are attachedtogether using an explosion bonding technique known in the art.Explosion bonding fuses the dissimilar materials of the base plate 606and cap 608 to provide a seal-free interface therebetween.

Preferably, the base plate 606 is made from the same material as thebody 27 to simplify their attachment to each other. In this exemplaryembodiment, both are made from aluminum. Before attaching an assembly ofthe base plate 606 and cap 608 to the body 27, the internal inert gaschannel 610 is machined in the body 27. A surface of the base plate 606forms an outer surface of the internal inert gas channel 610. Theillustrated shape and size of the internal inert gas channel 610 is onlyexemplary and may have a different shape and size. Further, the locationof the internal inert gas channel 610 is only exemplary and may be movedfrom the illustrated location within the body 27.

The explosion bonded base plate 606 and cap 608 are attached to theouter surface of the body 27. An energy beam welding method may beemployed to attach the base plate 606 to the body 27. For example, alaser beam or electron beam may be used and provide a highly focusedbeam of energy to weld the materials together. In certain embodiments,the base plate 606 is electron beam welded to the body 27.

The valves are then connected to the cap 608. In certain embodiments, ametal seal is employed to form a seal between the valves 30, 31 and thecap 608. Metal seals, as opposed to polymeric o-rings, have increasedchemical resistance. In certain embodiments, a W-shaped metal seal isemployed at the interface between the valves 30, 31 and the cap 608.Metals seals are also advantageous due to their ability to withstandhigher loads without excessively deforming as compared to polymerico-rings. The metal seal may be coated or not.

Once assembled, the inert gas flows from the internal inert gas channel610 and through line 646 before reaching inert gas valve 30(a).Advantageously, the bond between the body 27 and the base plate 606 isan electron beam weld having no separate seals. The bond between thebase plate 606 and the cap 608 is an explosion bond having no separateseals. A releasable metal seal is employed between the valves 30(a),31(a) and the cap 608 allowing removal of the valves 30(a), 31(a) forinspection, cleaning, and maintenance.

The inert gas valve 30(a) output port is in flow communication withreactant gas valve 31(a) via line 648. Line 648 is preferably not sharedamong components of the internal inert gas channel 610 and requires noseals besides at the inlet and outlet for the line 648. Preferably, theseals sealing the exit from line 646, the inlet to line 648, the outletfrom line 648, the exit from line 622, and the inlet to line 624 aremetal. Advantageously, the use of metal seals can increase the seal lifeover conventional polymeric seals and enhance contamination exclusiondue to their high chemical resistance.

Reactant gas valve 31(a) is in flow communication with line 648. Inaddition to allowing or preventing reactant gas A from reaching thecentral bore 28 of the manifold assembly 10 from line 622, the reactantgas valve 31(a) is further configured to allow or prevent flow of inertgas through line 624 and into the central bore 28 of the manifoldassembly 10. Thus, the reactant gas valve 31(a) may be configured toseparately allow or prevent the inert gas and the reactant gas A fromentering line 624.

In a preferred embodiment, reactant gas valve 31(a) is a three portvalve. A first port of reactant gas valve 31(a) is in flow communicationwith line 622 and receives reactant gas A. A second port of reactant gasvalve 31(a) is in flow communication with line 648 and receives an inertgas. A third or exit port for reactant gas valve 31(a) is in flowcommunication with the central bore 28 of the manifold assembly 10 vialine 624.

Controlling the machining tolerances of the base plate 606 and cap 608can aid in aligning a first portion of a line on a first side of aninterface with a second portion of that same line on a second side ofthe same interface thereby reducing recirculation or voids within themanifold assembly 10. Controlling the surface finish and flatness on themating surfaces of the sub-components of the manifold assembly 10 canaid in sealing adjacent sub-components. In certain embodiments, a 16 to32 micro finish surface is maintained on the sealing surfaces.

The control system controls one or more of the valves 30, 31 toselectively allow or prevent one or more gases from reaching the centralbore 28 of the manifold assembly 10. Advantageously, the embodiments ofthe manifold assembly 10 reduce the need for conventional seals atinterfaces between components of the manifold assembly 10. Reducing thenumber of conventional seals decreases the chance of forming dead legsor zones. For ALD operation, reducing dead legs reduces the duration ofpurging needed to avoid interaction of reactants upstream of thereaction space. Such interaction could lead to contamination ornon-uniformities in the deposition on substrates. Where interfaces mustoccur, advanced fabrication techniques may be employed to minimize theformation of dead zones. These fabrication techniques include electronbeam welding, employing metal seal technology, explosion bonding, andthe like. The manifold assembly 10 further employs discrete heaters 180to individually control the temperature of the various gases enteringthe central bore 28 of the manifold assembly 10.

Although the present invention has been described in terms of a certainpreferred embodiments, other embodiments apparent to those of ordinaryskill in the art also are within the scope of this invention. Thus,various changes and modifications may be made without departing from thespirit and scope of the invention. For instance, various components maybe repositioned as desired. Moreover, not all of the features, aspectsand advantages are necessarily required to practice the presentinvention.

1. An atomic layer deposition (ALD) device, comprising: a dispersionassembly configured to disperse gas; an inlet manifold block connectedupstream of the dispersion assembly and having a bore; a first reactantvalve mounted on the inlet manifold block and configured to control asupply of a first reactant gas to the bore; a second reactant valvemounted on the inlet manifold block and configured to control a supplyof a second reactant gas to the bore; an inert gas valve mounted on theinlet manifold block and configured to control a supply of an inert gasto the bore; and a first spacer block mounted directly on the inletmanifold block, and wherein at least one of the first reactant valve,the second reactant valve, and the inert gas valve is mounted directlyon the first spacer block.
 2. The ALD device of claim 1, wherein thefirst spacer block is welded to the inlet manifold block.
 3. The ALDdevice of claim 1, wherein the first spacer block comprises a base plateand a cap.
 4. The ALD device of claim 3, wherein the base plate and thecap are fused together.
 5. The ALD device of claim 1, wherein the firstspacer block is disposed between the inlet manifold block and the firstreactant valve.
 6. The ALD device of claim 5 further comprising a metalseal formed between the first spacer block and the first reactant valve.7. The ALD device of claim 5, wherein the inlet manifold block has aninternal inert gas channel, and wherein the inert gas valve isconfigured to control a supply of an inert gas from the internal inertgas channel to the first reactant valve.
 8. The ALD device of claim 7,wherein the internal inert gas channel extends through the first spacerblock.
 9. The ALD device of claim 5 further comprising a second spacerblock, the second spacer block being disposed between the inlet manifoldblock and the second reactant valve.
 10. The ALD device of claim 1,wherein the first spacer block is mounted directly on the inlet manifoldblock by an electron beam weld, a metal seal, or an explosion bond, andwherein at least one of the first reactant valve, the second reactantvalve, and the inert gas valve is mounted directly on the first spacerblock by an electron beam weld, a metal seal, or an explosion bond. 11.The ALD device of claim 1, wherein the first spacer block is mounteddirectly on the inlet manifold block without any intervening sealelements.
 12. The ALD device of claim 11, wherein at least one of thefirst reactant valve, the second reactant valve, and the inert gas valveis mounted directly on the first spacer block without any interveningseal elements.
 13. The ALD device of claim 1, wherein dead legs are notformed at a first bond interface between the first spacer block and theinlet manifold block, and wherein dead legs are not formed at a secondbond interface between the first spacer block and at least one of thefirst reactant valve, the second reactant valve, and the inert gasvalve.